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Homework Help: Can someone help with this problem

  1. Jan 12, 2007 #1
    1. The problem statement, all variables and given/known data

    Find the derivitive of y = (e^cx)(c sin x – cos x)

    2. Relevant equations

    None

    3. The attempt at a solution

    c(e^cx)(c sin x – cos x) + (c cos x + sin x)(e^cx)

    The answer is { (1+c^2)((e^cx)sin x)
     
  2. jcsd
  3. Jan 12, 2007 #2

    TD

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    You're doing fine, they are the same! Try to simplify :smile:
     
  4. Jan 12, 2007 #3
    it is right .... hey TD ..what he should simplify
     
  5. Jan 12, 2007 #4

    TD

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    If you look well, you see the terms in cos(x) are opposite, they cancel out.
     
  6. Jan 12, 2007 #5
    ah ok he did it .... i thought there is somethin' else i missed thanks for the reply
     
  7. Jan 12, 2007 #6
    Thanks TD i see how it works now :smile:
     
  8. Jan 12, 2007 #7

    TD

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    You're welcome!

    When you see that the given answer doesn't match your "longer" answer, always think of simplifying, it may just be correct after all :smile: !
     
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